3.05g of hydrated copper sulfate produces 1.94g of anhydrous copper sulfate.Assuming complete removal of all water of crystallisation,determine the formula of the hydrated copper sulfate
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CuSO4.xH2O --> CuSO4 + xH2O
3.05 g.....................1.94 g.......y
g H2O = 3.05 - 1.94 = 1.11 g
mols CuSO4 = 1.94/159.5 = 0.0122
mols H2O = 1.11/18.01 = 0.0616
Convert these numbers to mols H2O for 1 mol CuSO4. That's
mols CuSO4 = 0.0122/0.0122 = 1.000
mols H2O = 0.0616/0.0122 = 5.04 which rounds to 5 in whole numbers so the formula is CuSO4.5H2O
To determine the formula of the hydrated copper sulfate, we need to calculate the amount of water of crystallization in the compound.
1. First, calculate the mass of water lost during the dehydration:
Mass of water lost = Mass of hydrated copper sulfate - Mass of anhydrous copper sulfate
Mass of water lost = 3.05g - 1.94g
Mass of water lost = 1.11g
2. Next, calculate the moles of water lost using the molar mass of water (H2O):
Moles of water lost = Mass of water lost / Molar mass of water
Molar mass of water = 2(1.008g/mol) + 16.00g/mol = 18.02g/mol (using atomic weights of hydrogen and oxygen from the periodic table)
Moles of water lost = 1.11g / 18.02g/mol
Moles of water lost = 0.0615 mol
3. Because copper sulfate contains 5 water molecules per formula unit (CuSO4 · 5H2O), we can use the following ratio to determine the moles of copper sulfate:
Moles of copper sulfate = Moles of water lost / 5
Moles of copper sulfate = 0.0615 mol / 5
Moles of copper sulfate = 0.0123 mol
4. Finally, determine the formula of the hydrated copper sulfate:
The formula of hydrated copper sulfate is CuSO4 · 5H2O
To determine the formula of the hydrated copper sulfate, we need to calculate the number of moles of hydrated copper sulfate and anhydrous copper sulfate.
First, let's calculate the number of moles of anhydrous copper sulfate:
Mass of anhydrous copper sulfate = 1.94g
To calculate the number of moles, we will use the formula:
Number of moles = Mass / Molar mass
The molar mass of copper sulfate (CuSO4) is:
Copper (Cu) = 63.55 g/mol
Sulfur (S) = 32.07 g/mol
Oxygen (4xO) = 4x16.00 g/mol
Molar mass of CuSO4 = 63.55 + 32.07 + (4x16.00) = 159.61 g/mol
Number of moles of anhydrous copper sulfate = 1.94g / 159.61 g/mol = 0.01214 mol
Now, let's calculate the number of moles of water present in the hydrated copper sulfate:
Mass of hydrated copper sulfate = 3.05g
Mass of anhydrous copper sulfate = 1.94g
Mass of water = Mass of hydrated copper sulfate - Mass of anhydrous copper sulfate
Mass of water = 3.05g - 1.94g = 1.11g
To calculate the number of moles, we will use the formula:
Number of moles = Mass / Molar mass
The molar mass of water (H2O) is:
Hydrogen (2xH) = 2x1.01 g/mol
Oxygen (O) = 16.00 g/mol
Molar mass of H2O = 2x1.01 + 16.00 = 18.025 g/mol
Number of moles of water = 1.11g / 18.025 g/mol = 0.06148 mol
Next, we need to determine the ratio of moles of copper sulfate to moles of water. To do this, we divide the number of moles of copper sulfate and water by the smallest value.
Number of moles of copper sulfate = 0.01214 mol
Number of moles of water = 0.06148 mol
Dividing both values by the smallest value (0.01214 mol), we get:
Number of moles of copper sulfate = 1 mol
Number of moles of water = 5 mol
Therefore, the formula of the hydrated copper sulfate is CuSO4·5H2O.